Gun sight



J. D. TEAR GUN SIGHT July 30,

Filed Sept. 25, 1940 INVENTOR JAM ES D.TEAR

ATTORNEY Patented July 30, 1946 UNITED STATES PATENT QFFICE James D. Tear, Great Neck, N. Y., assignor to Ford Instrument Company, Inc., Long Island City, N. Y., a corporation of New York Application September 25, 1940, Serial No. 358,2 46 p 11 Claims.

This invention relates to sights for gun's, especially of the type in which the gun is driven at an adjustable rate and the sight is automatically displaced from the gun in proportion to therate so that the gun leads the sight to allow for the movement of the target during the time of flight of the projectile.

In sights of this type, such as is shown in United States Patent No. 1,067,859, it is customary to set the deflection of the sight from the gun by simply angularly displacing the bore of the sight from the bore of the gun in proportion to the rate of train or the rate of change in bearing of the target and the time of flight of the projectile, so that the gun leads the sight. In the prior art, when the sight lagged behind the target due to an under set rate of train, and an increased rate of train was set up, although the gun was automatically trained at the increased rate, the sight was further displaced from the target, as the displacement of the sight from the gun is proportional to the rate of train. The increase in the displacement of the sight from the gun, neutralizing for the moment the movement in train of the sight, caused operators in their efforts to keep up with and on the target to give further and greater changes in the rates of train than were required. When the sight thus overcorrected did come on the target and the rate of train was then decreased, the angular displacement of the sight from the gun, known as deflection, was correspondingly decreased, thereby causing the sight to be moved further ahead of the target. This hunting action, especially when firing at high speed targets, made it extremely difficult to set the rate of train correctly and keep the sight on the target.

,It is an object of this invention to eliminate this erratic action of the sight by providing a control mechanism in which the correction to the rate of the gun initially moves the sight in a direction relative to the gun to bring the sight on the target and then the sight is moved in the reverse direction to its correct position relative to the gun corresponding to the new rate of movement of the gun. While this second movement of the sight is in a direction to move the sight from the target, it neutralizes the first movement and adds the required correction in deflection. In order to train the gun to cause the sight to be automatically brought back on the target an excess correction must be temporarily introduced and gradually reduced as the sight approaches the target until the optimum condition is attained.

The single figure of the drawing shows an embodiment of the invention in schematic perspective in its neutral or secured position.

Referring now to the drawing, the gun I and the sight 2 are mounted on conventional eleva tion trunnions 3 and 4 respectively. The gun trunnions 3 'are'su'pported on brackets 5 rigidly supported by a turntable 6 which is mounted for rotation about a center bearing 7. The sight trunnions 4 are mounted in a yoke 8 having -a bushing 9 depending therefrom. The bushing 9 and the yoke B are rotatably mounted on a stud l projecting vertically from the turntable 6 into the bore of the bushing 9.

Surrounding the turntable 6 is a stationary training rack l l and meshing therewith is a pinion I2 rotatably mountedin a bracket l3 carried by the turntable 6. On the turntable E is a variable speed device M which is shown as the two ball friction type disclosed in United States Pat ent No. 1,317,915, although any suitable type of variable speed drive such as mechanical, hydraulic or electrical, may be used. The output shaft i drives the pinion l2 through gears l6 and ll.

' The constant speed input for the variable speed device M is provided by a constant speed motor [8 acting through shaft l9 and worm 28. The rate control member 2! of the variable speed device I 4 is moved by a control handle 22 pivoted on vertical trunnions 23in a bracket 24 mounted on the turntablefi. ,The inner end 25 of the handle 22 fits between two lugs 29 On the rate control member 25. The direction of rotation of the output of the variable speed device is such that as the handle is pointed tothe right, that is, moved clockwise about its trunnions '23, .theturntable will be rotated in the .same direction and as the handle is pointed to the leftthe turntable will rotate counterclockwise. It is evident that the rate of rotation of the-turntable is substantially proportional to the displacement of the handle 22 from its central position, in which position the output of the variable speed device is stationary and there is nomovementof the turntable.

On the control member 2! of the variable speed device I4 is a rack 27 meshing with a pinion 28 on arateshaft 29 which drives one side of a differential 30, the other side of which is connected by a shaft 3| to pinion 32 to position the rate control member 33- of a second variable speed device 34. The output shaft 35 of this variable speed device is connected to the third or center member of the differential by a shaft 36. The input member of variable speed device 34 is driven by a worm 31 on shaft 19 driven by motor [8.

A second differential 38 connects a branch 29a of the rate shaft 29 and the output shaft to shaft 39 which acts through a multiplier unit t!) and a shaft 4| to rotate the sight 2 on its vertical axis by means of a worm 42 on the shaft 4| mesh ing with a worm gear 43 carried-by the bushing 9.

The multiplier unit 49 may be of the type shown in United States Patent No. 2,194,477 or any other suitable type. The shaft 39 is one input to the multiplier, thehandcrank 44 is the offset of the sight from the gun is generally des-.-

As will be herein-:

ignated as deflection (Ds). after explained the position of the input shaft'39 to the multiplier 40 represents. the rate of. train and corresponds to the position of the rate control member 2| of the variable speed device I4, when the rate control member 33 of the variable W speed device 3.4 is. at its zero or'neutral: position.

Operation The operation of the apparatus will be analyzed and described on the basis that the movement of the output of the differential 38' is the combination of two separate movements, one due to the movement of control member 2| which is connected directly to diiferential 33 through the branch 29a of shaft 29, and a second movement dueto the movement of control member 2| which is connected to differential 38 through differential 30 and variable speed device 3'4. The second movement is completed later than the first because of the mechanical lag in the follow-up action of the variable speed device. The second movement is in the opposite direction to the first and is of greater magnitude, as will be: described hereinafter.

With the apparatus in its secured position, with the control members of the variable speed devices l4 and 34 in their neutral positions as shown, the operator points handle 22 in a direction, say to the right, to swing the turntable to the right to pick up the target. The member 2| is moved to its extreme position without regard to the deflection in order to bring the sight on the target as quickly as. possible, As the s ght swings towards the target the operator cra s the time of flight value into the multiplier 40 by crank 44. I

When the sight approaches the target, the ra e of t i of the tur table 6 is reduced and a iusted to the exact rate of change of bearing (dB) of the. target by adjusting the position of rate control member 2| by moving'handl'e 22' as hereinafter described. The sight is thereby set for the c rres o d g deflection (Us) by reason of the output of differential 38 and multiplier 40.

To illustrate the operation of the apparatus to effect a c ange in. rate of train, it is assumed that the tar et. is moving to the right and the rate of change of bearing (dB), represented by th positi n of s aft 3-! and the ha dle 22, is underset. that is. the sight is lagging behind the target and a higher rate (dB') andtherefore a greater deflection (D's) are required.

T e ooerator points handle 22 further to the right and immediately sees the sight move to the right or towards the target. due to the movement of shaft 39 which is directly connected to handle 22 through member 2 differential 38 and the branch 29a of s aft 29. At the same time, shaft 29 t rou h differential 30. moves the control member 33 of variable speed device 34 and after the mechanical time la in the action of variable s eed dev ce 34. s aft 35 moves shaft 39 through difieren-tial 38 in t e o posite direction and in an amount canal to the first movement plus the desired correction to the rate of train or (dB'-dB).

The ratio of the gears in the branch 29a and on shaft 29 between differential 38 and pinion 28 is selected as (k) and the gears associated with variable speed device 34 are such that the ratio of transmission to differential 38 from gear 28 through device 34 is (1+k). It will therefore be seen that for any change (dB'dB) in the setting of member 2| by handle 22, there will be a resultantv change in the output of differential 38,

i. e. shaft 39, equal to Ic(dB"dB) (l+k) (dB-dB) which equals (dB'dB). The portion 7c(dBdB) is. applied directly and immediately through shaft 23"'and the branch 2.3a and the portion +-('1+7s) (dB -dB). is applied through difierential3il: and variable. speed device 34 with a slight time. lag. The corresponding final change in deflection (Ds'D's) is equal to (dB'dB) t, where t is the time of flight of the projectile.

When no changes in the rate of. train are being made, the control member 33 of variable speed device 34 is automatically brought to its mid-position as the output shaft 35 is connected to the control member through. differential 30 by shaft 36, it being restored to this position after each change in bearing rate by the restoring ac-' tion of the shaft 36. It will thus be seen that this action is in effect that of a delayed followup that is, the resultant motion of shaft 35 is proportional to the motion of shaft 29.

- The invention is shown as applied to the training of. agun and the deflection of the associated sight, but it is apparent and intended that the invention shall be applied to other movements of the gun, such as elevation. It is also contemplated that various dials may be applied to the mechanism for indicating the instantaneous values represented by different parts of the mechanism as desired.

It is evident that various changes may be made in the form, construction and arrangement of the various parts of the mechanism. without departing from the spirit of the invention as defined. in the appended claims.

I claim:

1'. In combination, a gun mounted for angular movement, a member having a movement proportional to the angular velocity of the gun, a sight mounted for angular movement relative to the gun, differential means actuated in part by the movement of the member for directly moving the sight towards the gun for an increasing rate of angular velocity of the gun, and other means for actuating the differential means by the movement of the member for moving with delayed action the sight relative to the gun in reverse direction.

2. In combination, a gun mounted for angular movement, a member having a movement proportional to the angular velocity of the gun, a sight mounted for angular movement relative to the gun, differential means actuated in part by the movement of the member for directly moving the sight towards the gun for an increasing rate of angular velocity of the gun in one ratio, and other means for actuating. the differential means by the movement of the member for moving with delayed action the sight relative to the gun in the reverse direction in another ratio.

3. In combination, a gun mounted for angular movement, a member having a movementproportional to the angular velocity of the gun, a

sight mounted for angular movement relative to the gun, a differential, means connecting the member directly to the differential in one ratio, a delayed action follow-up, means connecting the member to the differential through the follow-up in another ratio, and means connecting the output of the differential to angularly displace the sight relative to the gun.

4. In combination, a gun mounted for angular movement, a member having a movement proportional to the angular velocity of th gun, a sight mounted for angular movement relative to the gun, a difierential, means connecting the member directly to the differential in one ratio, a delayed action follow-up, means connecting the member to the differential through the follow-up in another ratio, a multiplier, means connecting the output of the differential to one input of the multiplier, means settable in accordance with a function of range connected to the other input of the multiplier, and means connecting the output of the multiplier to angularly displace the sight relative to the gun.

5. In combination, a gun, power means for angularly moving the gun, said power means including a settable member adapted to control the angular velocity of the gun, a sight mounted for angular movement relative to the gun, differential means actuated in part by the movement of the member for directly moving the sight towards the gun for an increasing rate of angular velocity of the gun, and other means for actuating the differential means by the movement of the member for moving with delayed action the sight relative to th gun in the reverse direction.

6. In combination, a gun, power means for angularly moving the gun, said power means including a settable member adapted to control the angular velocity of the gun, a sight mounted for angular movement relative to the gun, differential means actuated in part by the movement of the member for directly moving the sight towards the gun for an increasing rate of angular velocity of the gun in one ratio, and other means for actuating the differential means by the movement of the member for moving with delayed action the sight relative to the gun in the reverse direction in another ratio.

7. In combination, a gun, power means for angularly moving the gun, said power means including a settable member adapted to control the angular velocity of the gun, a sight mounted for angular movement relative to the gun, a differential, means connecting the member directly to the differential in one ratio, a delayed action follow-up, means connecting the member to the differential through the follow-up in another ratio, and means connecting the output of the differential to angularly displace the sight relative to the gun.

8. In combination, a gun, a variable speed device including a control member adapted to angularly move the gun, a sight mounted for angular movement relative to the gun, a differential, means connecting one side of the differential to the control member, means connecting the output of the differential to angularly position the sight relative to the gun, a second variable speed device including a control member, a second differential, means for connecting the first control member to one side of the second differential,

means for connecting the output of the second difierential to the second control member and means for connecting the output of the second variable speed device to the other side of the first differential and to the other side of the second differential, whereby th output of the first differential is responsive immediately to the move ment of the first control member in one direction and responsive in delayed action to the movement of the first control member in the reverse direction.

9. In combination, a rotatabl mount, power means for angularly moving the mount, a variable speed device associated with the power means, said variable speed device including a control member for controlling the angular velocity of the mount, a sight mounted on the rotatable mount and angularly adjustable relative thereto, a control handle, means actuated by the control handle for positioning the control member, a differential having two input members and an output member, means connecting the output member of the differential to the sight for angularly adjusting the sight relative to the mount, means connecting the control member to one input member of the difierential to displace the sight in a direction responsive to movement of the control member, follow-up means responsive with delayed action to the movement of the control member, and means connecting the output of the follow-up means to the second input member of the differential to displace the sight in the opposite direction.

10. In combination, a rotatable mount, power means connected for angularly moving the mount, a variable speed device associated with the power means and including a control member for controlling the rate of movement of the mount, a sight mounted on the rotatable mount and angularly adjustable relative thereto, a control handle, means actuated by movement of the control handle for moving the control member to change the angular rate of movement of the mount, means actuated by the movement of the control member for moving the sight relative to the mount in the direction of the change of rate of movement of the mount, and delayed action follow-up means actuated by the movement of the control member for moving the sight in the reverse direction relative to the mount.

11. In combination, a rotatable mount, power means connected for applying angular movement to the mount, a variable speed device associated with the power means and including a control member for controlling the rate of angular movement of the mount, a sight mounted on the rotatable mount for angular displacement relative thereto, a control handle, means actuated by movement of the control handle for moving the control member to change the rate of angular movement of the mount, means simultaneously actuated by the movement of the control handle for causing angular displacement of the sight in the direction of the change of rate of angular movement of the mount, and delayed action follow-up means controlled by the movement of the control handle and operative to remove the angular displacement of th sight caused by movement of the control handle.

JAMES D. TEAR. 

